This invention relates generally to contacts used in electrical connectors and, more particularly, to contacts used in conjunction with capacitive filters.
Known electrical connectors are capable of communicating data signals at relatively high rates. The signals are communicated between a connector and another connector and/or a circuit board via one or more contacts. Electrical noise in the signals may increase as the speed at which the signals are communicated increases. In some known connectors, one or more capacitive filters are provided to filter out noise from the signals. For example, some known connectors include one or more capacitors provided in series with contacts to filter out noise in the signals communicated through the contacts. The capacitive filter may be disposed on the circuit board to which the connector is mounted. One or more conductive traces in the circuit board electrically couple the contacts with the capacitive filter. Signals communicated by the connector propagate through the contacts and the capacitive filter via the conductive traces.
Communicating signals through the conductive traces and the capacitive filter increases the total path over which the signals propagate. For example, directing the signals from the contacts and through conductive traces and a capacitive filter before communicating the signals to a final destination adds to the total length over which the signals travel before reaching the destination. Increasing the total length over which the signals travel, that is, the signal path length, may increase the time delay skew in signals communicated through the contacts and capacitive filter. For example, in a connector that communicates differential pair signals over at least two contacts, the additional signal path length that is required to direct the signals through the capacitive filter may increase the time delay skew between the signals.
Additionally, communicating signals through the conductive traces and the capacitive filter may consume more of the already limited real estate on a circuit board. For example, a relatively large number of conductive traces and capacitive filters may be required in a circuit board in order to filter signals communicated using connectors that have several contacts. The large number of conductive traces and capacitive filters may consume a relatively large amount of available area of the circuit board to which the connector is mounted and prevent this area from being used for other connectors or components.
Another drawback for circuit board-mounted capacitors and other components is the need for vias in the circuit board. The vias may include small plated through holes in the circuit board that carry signals between the capacitors or components and conductive traces in the circuit board. For example, vias may carry signals from inside a controlled impedance layer of the circuit board up to the surface of the circuit board, and then back down again into the circuit board. Such a signal propagation path through the circuit board adds discontinuity to the propagation path and may cause signal degradation.
Thus, a need exists for a contact assembly that communicates and filters signals, while minimizing any increases to the signal length, reducing the amount of area that is used on a circuit board to communicate and filter the signals, and/or decreasing discontinuities in signal propagation paths through the circuit board.